Perhaps you've read Revelation 12:7-12 and understood it to be describing the fall of Satan in the Beginning. That is a reasonable thing to do, as the passage describes a war between "the dragon and his angels" and the archangel Michael and the good angels with him. The bad guys are defeated and "thrown down" from Heaven to earth, as they plainly have no place in the heavenly realm anymore. So Satan is forced to make the earth his abode, where he flails about in "great wrath" and rages against the authority of God.

But this conventional narrative about the fall of Satan doesn't seem to have all the gaps filled. For instance, there are several instances in the Old Testament where Satan seems to be fully capable of being in Heaven and even having some interaction with God there. Job 1 has him present himself before God with other beings, and he accuses God of pampering Job. In Zechariah 3:1-5 Satan appears in God's presence to accuse Joshua, the high priest.

Perhaps, then, Revelation 12:7-12 isn't describing the original, primordial fall of Satan but a different defeat he suffers, namely the crushing of his power to accuse God's people of sin. This seems borne out by the text itself. In verse 10, after Satan is thrown down, the heavenly throng sings out.

"Now the salvation and the power and the kingdom of our God and the authority of his Christ have come, for the accuser of our brothers has been thrown down, who accuses them day and night before our God."

So what is Satan's defeat and expulsion from Heaven here? It coincides with the loss of his ability to point out the sins of God's people and see them condemned. And how did Satan lose that power? When Jesus, the Christ mentioned in verse 10, died on a cross. Or, in more general terms, through the whole life and ministry of Jesus.

So may I ask you, does Satan have grounds to accuse you before God? Of course he does; you and I sin against the Lord every day. How then can we be found among the "brothers" of the heavenly throng of verse 10? How can we possibly escape condemnation? Only if we are found in Christ. Only if Jesus' triumph over the devil has become our triumph as well. Only if Jesus' blood covers our sins and he clothes us in his own righteousness instead.

When a man or woman or child turns to God through faith in Jesus Christ, the ground of Satan's accusations is gone because Jesus' blood covers him or her. Sin is atoned for. There is nothing for Satan to point out; he can only stand mute and baffled. So Revelation 12:11 can even say, "they have conquered (Satan) by the blood of the Lamb and by the word of their testimony." Do you want to conquer Satan? Do you want to win the most important spiritual battle? Then you must be covered by the blood of Jesus Christ, the Lamb of God, and you will win along with Christ who has already crushed Satan's head decisively.